Electric coolant pump

ABSTRACT

The invention relates to an electric coolant pump comprising a pump housing, a rotating conveying element for accelerating the coolant, a pump shaft passing through the pump housing and on which the conveying element is mounted, an electric motor for driving the pump shaft; and a control circuit. The conveying element is arranged in a pump chamber formed by the pump housing and a spiral lid. The electric motor is arranged in a motor chamber formed by the pump housing and motor lid. Furthermore, a control circuit chamber is formed in the pump housing, for the control circuit. The control circuit chamber has an opening through which the control circuit can be inserted into the control circuit chamber.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to German Patent Application No. 10 2020 128 170.6 entitled “Elektrische Kühlmittelpumpe”, filed Oct. 27, 2020, which is hereby incorporated herein in its entirety by reference, including the English translation thereof.

TECHNICAL FIELD

The invention relates to an electric coolant pump, in particular for conveying cooling liquid in a vehicle.

BACKGROUND

Electric coolant pumps comprise an electric motor for driving a rotating conveying element (e.g. a pump impeller). The associated control circuit for the electric motor is typically positioned in or on the pump housing. Round printed circuit boards are conventionally used in such cases, the control circuit being disposed thereon as disclosed in DE 10 2018 104 784 A1. WO 2019 233 600 A1 describes a further coolant pump with a control circuit which is disposed in the pump housing. CN 11 03 19 027 A discloses a coolant pump with a control circuit arranged laterally on the pump housing. A disadvantage with the above-mentioned installation locations of the control circuit is that the control circuit must already be installed in an early assembly stage and is then difficult to access for maintenance or repair purposes. Furthermore, the individual and/or subsequent adaptation of the control circuit to different usage purposes is rendered more difficult.

SUMMARY

It is thus the object of the present invention to provide an electric coolant pump which is very easy to assemble and highly variable.

The electric coolant pump comprises a pump housing, a rotating conveying element for accelerating the coolant to be conveyed, a pump shaft passing through the pump housing and on which the conveying element is mounted, an electric motor for driving the pump shaft and a control circuit. The conveying element is arranged in a pump chamber formed from the pump housing and a spiral lid, and the electric motor is arranged in a motor chamber formed from the pump housing and a motor lid. In the pump housing is a control circuit chamber, inside of which the control circuit is arranged, wherein the control circuit chamber has an opening, through which the control circuit is insertable into the control circuit chamber.

In this way, simple assembly of the control circuit is possible even at the end of pump manufacture. This also facilitates the adaptability and variability of the electric coolant pump since the pump housing including the conveying element, pump shaft, spiral lid, motor and motor lid can be pre-produced as a standard assembly and, as a final step, can be provided with an individual control circuit. Even during operation of the pump, the control circuit remains easily accessible and so maintenance and repair work which may be required are facilitated. Since the control circuit chamber constitutes an additional chamber besides the pump chamber and the motor chamber, the control circuit is separated with respect to the rest of the pump components. No further sealing is necessary in order to protect the control circuit, e.g. against the coolant flowing through the pump chamber.

The control circuit can be designed as an electronic control unit (ECU). Advantageous developments of the electric coolant pump in accordance with the invention are the subject matter of the dependent claims.

In an advantageous embodiment, the control circuit chamber can be arranged in the axial direction of the pump shaft between the pump chamber and the motor chamber. In this way, the control circuit can be arranged in physical proximity to the pump chamber and benefit from the cooling effect of the coolant conveyed in the pump chamber.

Furthermore, the insertion direction (i.e. the direction in which the control circuit can be inserted into the control circuit chamber) can be oriented perpendicularly with respect to the axial direction of the pump shaft.

In order to improve the thermal discharge effect of the coolant conveyed in the pump chamber on the control circuit, the control circuit chamber can be provided immediately adjacent to the pump chamber, i.e. merely separated from each other by a housing separating wall.

If the control circuit is fixed in the control circuit chamber by means of a thermal conductive paste or a thermal conductive pad, particularly in the direction of the pump chamber, this likewise increases the thermal discharge effect of the coolant conveyed in the pump chamber on the control circuit.

In a preferred embodiment, the control circuit chamber can extend in a U-shaped manner around the pump shaft. In this way, the largest surface contact possible with the pump chamber, and therefore a good thermal discharge effect, is ensured. In a particularly preferred manner, the control circuit is arranged on a U-shaped circuit board. This renders it possible to make good use of the available installation space. The space required for the coolant pump is reduced accordingly.

In a preferred embodiment, the opening of the control circuit chamber can be closed by a lid. This lid is preferably designed as a removable and/or reclosable lid. In this way, the control circuit is protected against dirt and damage. In a particularly preferred embodiment, the lid further comprises a connector plug for the control circuit. This lid therefore has a dual function as an electrical connection and as a cover or closure.

In a preferred embodiment, a leakage space for receiving escaping coolant can be provided adjacent to the control circuit chamber in the pump housing. If the control circuit chamber extends in a U-shape around the pump shaft, the leakage space can be formed around the pump shaft in particular in the spatial sector not occupied by the control circuit chamber. This also renders possible particularly good usage of the available installation space, which accordingly reduces the space required for the coolant pump.

In a preferred embodiment, a winding of the electric motor is contactable by insulation-displacement connections during insertion of the control circuit into the control circuit chamber. In this way, reliable contact can take place simultaneously with insertion of the control circuit into the control circuit chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail hereinunder by means of an exemplified embodiment with the aid of the accompanying Figures. In the drawing:

FIG. 1 shows a perspective view of an exemplified embodiment of the electric coolant pump;

FIG. 2 shows an exploded perspective view of the electric coolant pump of FIG. 1;

FIG. 3 shows a side view of the electric coolant pump of FIG. 1 without a lid for the control circuit chamber;

FIG. 4 shows a cross-sectional view through the pump housing; and

FIG. 5 shows a cross-sectional view through the pump housing along the sectional plane A-A in FIG. 4.

The structure of an exemplified embodiment of the electric coolant pump in accordance with the invention is described hereinunder with reference to the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

The electric coolant pump 1 illustrated in FIGS. 1 to 3 serves to convey a coolant in a coolant circuit not illustrated in more detail. This coolant circuit can serve e.g. for cooling of an internal combustion engine of a motor vehicle and can consist substantially of cooling ducts through which the coolant is supplied to the components to be cooled and then to a heat sink (e.g. radiator). In the simplest case, the coolant can be e.g. water or a dielectric cooling liquid, to which metal corrosion-inhibiting constituents are added.

The electric coolant pump 1 comprises a pump housing 2 as a main component. In the described embodiment, the pump housing 2 is produced from a metallic material, in particular aluminium. A pump shaft 4 is mounted centrally in the pump housing 2 by means of a bearing 3. The pump shaft 4 therefore passes through the pump housing 2. A pump impeller 5 is mounted in a first axial end region of the pump shaft 4. The pump impeller 5 serves as a rotating conveying element for acceleration of the coolant to be conveyed. A rotor 6 is mounted in a second axial end region of the pump shaft 4 on the opposite side of the pump housing 2. Together with the stator 7, the rotor 6 forms an electric motor 8 for driving the pump shaft 4.

Jointly with a spiral lid 9, the pump housing 2 forms a pump chamber in which the pump impeller 5 is arranged. A seal 10 between the pump housing 2 and spiral lid 9 ensures a connection between these components which is as liquid-tight as possible. On the opposite side of the pump housing 2, and together with a motor lid 11, the pump housing 2 in turn forms a motor chamber in which the electric motor 8 is arranged.

Furthermore, a control circuit chamber 12 is formed within the pump housing 2. As seen in the axial direction of the pump shaft 4, this control circuit chamber 12 is arranged between the pump chamber and the motor chamber. The control circuit chamber 12 is formed in a substantially shaft-like manner and has a rectangular opening 13. A control circuit 14 for the electric coolant pump 1, i.e. more precisely for the electric motor 8, is arranged in this control circuit chamber 12. The insertion direction, in which the control circuit 14 is inserted into the control circuit chamber 12, is oriented perpendicularly (orthogonally) to the axial direction of the pump shaft 4.

The control circuit 14 is designed as an ECU and arranged on a U-shaped circuit board which has been inserted into the control circuit chamber 12 through the opening 13. The opening 13 is closed by means of a lid 15. Connector plugs 16 are formed on the lid.

During operation of the electric coolant pump 1, the pump impeller 5 is driven by the electric motor 8 operated by means of the control circuit 14. The coolant located in the pump chamber is accelerated by the pump impeller 5 and exits through the pump outlet 17 formed on the spiral lid 9. At the same time, coolant enters the pump chamber from the pump inlet 18 also formed on the spiral lid 9.

FIG. 4 shows a cross-sectional view through the pump housing 2, wherein the sectional plane coincides with the middle axis of the pump shaft 4. FIG. 5 shows a cross-sectional view through the pump housing 4 along the sectional plane A-A in FIG. 4. In the centre of the pump housing 2, a rotationally symmetrical aperture 19 for reception of the bearing 3 and of the pump shaft 4 is provided. The control circuit chamber 12 is formed in a U-shape around this aperture 19. In the axial direction of the pump shafts 4, the control circuit chamber 12 is separated by intermediate walls of the pump housing 2 from the pump chamber on one side (at the top in FIG. 4) and from the motor chamber on the other side (at the bottom in FIG. 4) and so, all in all, three separate chambers (control circuit chamber 12, pump chamber, motor chamber) are provided. The control circuit 14 is mounted in the control circuit chamber 12 by means of thermal conductive pads (not illustrated in more detail in the Figures) on the intermediate wall of the pump housing 2 facing the pump chamber.

As described above, the control circuit chamber 12 surrounds the pump shaft 4 in a U-shape. A leakage space 20 is formed in the spatial region around the pump shaft 4 in which the control circuit chamber 12 is not arranged. This leakage space 20 serves to receive coolant exiting in the region of the aperture 19.

Through the opening 13, the insertion of the control circuit 14 is also possible only after mounting of the remaining components such as bearing 3, pump shaft 4, pump impeller 5, rotor 6, stator 7, spiral lid 9, seal 10 and motor lid 11. This simplifies assembly, inter alia also because no ESD protection for the complete assembly is required. Furthermore, the adaptability and variability of the electric coolant pump 1 are increased since individually adapted control circuits 14 can be used independently of the remaining components of the electric coolant pump 1 in a later assembly step. Finally, maintenance and repair work on the control circuit 14 is facilitated since this can easily be removed from the control circuit chamber 12 after the lid 15 is opened.

The formation of the control circuit on a U-shaped circuit board together with the U-shaped control circuit chamber 12 ensures effective use of the available installation space. The integration of the leakage space 20 additionally increases the usage of the installation space.

Fixing the control circuit 14 directly to the intermediate wall of the pump housing 2 facing the pump chamber by means of thermal conductive pads or thermal conductive paste achieves particularly good thermal coupling to the coolant flowing through the pump chamber. In this way, the coolant can bring about a cooling effect on the control circuit 14.

The Figures of the drawings do not show an embodiment in which, during insertion of the control circuit 14 into the control circuit chamber 12, a winding of the electric motor 8 is contacted by insulation-displacement connections.

In the embodiment described above, the rotating conveying element is designed as a pump impeller 5 in order to accelerate the coolant to be conveyed. However, depending on the type of pump, another conveying element can also be used instead of the pump impeller 5. 

1. An electric coolant pump including: a pump housing; a rotating conveying element for accelerating the coolant to be conveyed; a pump shaft, passing through the pump housing, on which the conveying element is mounted; an electric motor for driving the pump shaft; and a control circuit; wherein: the conveying element is arranged in a pump chamber formed by the pump housing and a spiral lid; the electric motor is arranged in a motor chamber formed by the pump housing and a motor lid; in the pump housing, a control circuit chamber is provided, inside of which the control circuit is arranged; and the control circuit chamber has an opening, through which the control circuit is insertable into the control circuit chamber.
 2. The electric coolant pump according to claim 1, wherein the control circuit chamber is arranged in an axial direction of the pump shaft between the pump chamber and the motor chamber, and the insertion direction is oriented perpendicularly with respect to the axial direction of the pump shaft.
 3. The electric coolant pump according to claim 1, wherein the control circuit chamber is provided immediately adjacent to the pump chamber.
 4. The electric coolant pump according to claim 1, wherein the control circuit is fixed by means of a thermal paste or a thermal conductive pad in the control circuit chamber, particularly in the direction of the pump chamber.
 5. The electric coolant pump according to claim 1, wherein the control circuit chamber extends in a U-shaped manner around the pump shaft.
 6. The electric coolant pump according to claim 1, wherein the control circuit is arranged on a rectangular or U-shaped circuit board.
 7. The electric coolant pump according to claim 1, wherein the opening of the control circuit chamber is closed by a lid.
 8. The electric coolant pump according to claim 7, wherein, in the lid, a connector plug is provided for the control circuit.
 9. The electric coolant pump according to claim 1, wherein, adjacent to the control circuit chamber, a leakage space for receiving escaping coolant is provided in the pump housing.
 10. The electric coolant pump according to claim 1, wherein a winding of the electric motor is contactable by insulation-displacement connections when inserting the control circuit into the control circuit chamber. 